Spectral Measures: References

Question

I am trying to learn a little bit about the spectral theory of unbounded operators but the textbook we are using (Birman and Solomyak: Spectral theory of Self-Adjoint Operators in a Hilbert Space) is a little bit heavy going for me. Is there a "gentler" book to learn about these things?

Thank you.

Answer 1

I like Conway's treatment in section X.4 of A course on functional analysis. It builds on some previous results, including the spectral theory of bounded normal operators from Chapter IX.

I don't know if it is gentler.